I have an '06 Chevrolet Silverado 4x4 (Z71 Extended Cab). I just purchased a kit to replace all the suspension pieces in the front end, including upper/lower control arms, and inner/outer tie rod ends. The new pieces I purchased come with ball joints and bushings installed (went this way rather than replacing them in my old arms for ease of replacement). The ball joints and outer tie rod ends have grease zerks installed, which hopefully means they'll last longer than stock (though the stock ones have lasted ~179k miles). I've recently replaced the wheel bearings (in the last year). The shocks will be next on the list for replacement (all the way around).

This year of GM truck comes with a torsion bar front suspension. It has a screw in it which sets the ride height of the vehicle. I'm worried about getting everything set back to where it should be when I put it all back together. My questions are thus:

What can I do to ensure the truck gets back to proper ride height as I put it all back together? What have others done to ensure it gets back to proper ride height?

Are there any pitfalls to look out for as I do this work? Anything which wouldn't be readily apparent maybe even to a seasoned mechanic, but one who's never done this specific work before?

I realize I'll need to get an alignment after the fact. I may not be able to get one for a few days, so plan to do my best at measuring the installed tie rod lengths to ensure my toe is set as correctly as possible after reassembly, then get the truck in as soon as possible to get aligned. I'm not overly worried about too much wear on the tires, as I don't put that many miles on the truck as it is, possibly 10 miles per day on average.

2 Answers
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I seem to remember with the old Peugeot 205, which had torsion bar rear suspension, the method was to count the splines on the bars and make sure the new ones went in the same way. Remember that the new ones might sit higher as the old ones will have lost some of their spring, and that it will drop slightly as it settles. Also remember to do the final tightening with the vehicle's weight on it's wheels.

You can do a 'rough and ready' wheel alignment with two long bits of wood and some string - lay them along the plane of the wheels and measure the distance between them, then use trigonometry to calculate the toe angle. A third bit along the centre line of the truck will help to get it even on each side.

I will be using the same torsion bars. They go into a hexagonal pocket in the lower A-arm. I suspect they should have about the same drop as long as I have them set correctly. Getting them back to jump street is really what I'm worried about.
– Pᴀᴜʟsᴛᴇʀ2♦Sep 9 '17 at 21:01

Measure the ride height before you start - level ground and correct tyre pressures or at least with pressure you know and can repeat. My car has dimensions for the height from the ground to the edge of the wing directly above the highest point of wheel...

Also, measure the length of the tie rod ends and set the new ones to the same - not the most accurate but can be a good starting point.

The only other point is to only fully tighten the suspension bolts when the weight is back on the ground as then the bushes will be in the "natural " position.